Disordering and Electronic State of Cobalt Ions in Mechanochemically Synthesized LiCoO2

✍ Scribed by N.V. Kosova; V.F. Anufrienko; T.V. Larina; A. Rougier; L. Aymard; J.M. Tarascon

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 349 KB
• Volume: 165
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9493

✦ Synopsis

Mechanical activation (MA) combined with heat treatment at moderate temperatures was used to prepare disordered and highly dispersed LiCoO 2 starting from the mixtures of various cobalt precursors (CoOOH, Co(OH) 2 , and Co) and LiOH. Xray powder diffraction and IR spectroscopy were used to investigate the phase composition and the crystal structure of as-prepared samples, while the electronic state of cobalt ions was characterized by diffuse reflectance electron spectroscopy. MA of the LiOH+CoOOH mixture led to the formation of LT-LiCoO 2 with a cubic spinel-related structure. Heat treatment at 6001C of the latter resulted in the formation of HT-LiCoO 2 with a hexagonal layered structure similar to ceramic LiCoO 2 . However, as-prepared HT-LiCoO 2 is characterized by Co 3+ O 6 octahedra less perfect than those of ceramic LiCoO 2 . All MA-LiCoO 2 samples are exclusively described by localized d electrons.